This invention relates to at least one urinary catheter assembly comprising a urinary catheter having on at least a part of its surface a hydrophilic surface layer intended to produce a low-friction surface of the catheter by treatment with a liquid swelling medium prior to use of the catheter and a catheter package having a cavity for accommodation of the catheter.
Urinary catheters of the kind to which the invention pertains are known, inter alia, from EP-A-0 217 771, EP-A-0 586 324 and WO 94/16747, whereas various forms of catheter packages are known from U.S. Pat. Nos. 3,035,691, 3,648,704, 3,967,728, 4,204,527, 4,269,310, 4,379,506, 5,454,798, GB-A-2,284,764, DE-A-2,317839, EP-A-0 677 299 and DK Design Registration No. 0932 1986.
U.S. Pat. Nos. 3,648,704, 3,967,728, 4,269,310, GB-A-2,284,764 and EP-A-0 677 299 disclose a conventional urinary catheter assembly comprising a catheter of the kind where prior to insertion of the catheter into the urethra the tip of the catheter is to be lubricated with a gel-like lubricant and a package where such a lubricant is accommodated in a rupturable pouch connected with or located within the package itself adjacent to the tip of the catheter or supplied together with the catheter package for connection therewith prior to use of the catheter.
An important feature of any urinary catheter used for intermittent catherisation of the bladder of an incontinent user is the ability of the catheter to slide easily through the urethra without exposing the urethral walls to any risk of damage. Catheters of the kind to which the inventions pertains have been developed to meet this need by imparting an extremely low friction character to at least the part of the surface of the catheter which is actually introduced into the urethra. The low friction surface character is obtained by incorporating into the relevant part of the catheter at least a hydrophilic surface layer, typically in the form of a coating, and exposing this layer or coating to contact with a liquid swelling medium immediately prior to use.
In order to maintain the low friction surface character during location of the catheter in the urethra and subsequent with drawal therefrom and hereby reduce stinging pain it is further known to incorporate an osmolality promoting agent, such as NaCl, in the hydrophilic coating.
When catheters of this kind are used directly by end users outside the medical environment of a hospital or a clinic, e.g. by or tetraplegic patients who often have a very poor dexterity, and therefore need a very simple insertion procedure, the most common liquid swelling medium used for preparation of the catheter immediately prior to use would be normal tap water.
In order to reduce the risk of infection inherent with the performance of intermittent catherisation of the bladder both the actual swelling medium used and the environment in which the catherisation is performed need, to be as clean and antiseptic as possible. Evidently, this need may be very difficult to meet in many daily life situations, as where catherisation must be performed outside the users normal daily environment, e.g. in public toilets, where neither the water supply nor the general state of cleanliness can be expected to be of a sufficiently high standard. Moreover, many disabled users have severe difficulties in entering available toilet rooms due to simple physical barriers like narrow access ways, stairs and the like.
On this background, it is the object of the invention to improve and facilitate the performance of intermittent urinary catherisation in any type of environment by providing a ready to use urinary catheter assembly comprising a catheter which can be withdrawn from its package and is prepared for direct insertion in the urethra and in a substantially sterile condition, whereby the general quality of life for users of intermittent catherisation would be greatly improved.
In order to meet this and other objects of the invention, as set forth in the following, a urinary catheter according to the invention is characterised in that the package includes a compartment having walls of a gas impermeable material, said compartment accommodating said liquid swelling medium for provision of a ready-to-use catheter assembly.
The term xe2x80x9cgas impermeablexe2x80x9d material should be understood in this context to mean any material that will be sufficiently tight against diffusion by evaporation of the actual liquid swelling medium for a period exceeding the recommended shelf life time of the catheter assembly which could be up to five years, typically 36 months.
In a first series of embodiments of the urinary catheter assembly of the invention the catheter package as a whole is made of a gas impermeable material and the compartment for the liquid swelling medium is in liquid flow communication with the cavity for accommodation of the catheter.
In one preferred embodiment of this kind the catheter package may be formed from two sheets of gas impermeable film material connected with each other by a gas impermeable joint defining said compartment and the cavity for accommodating the catheter.
Thereby, the preparation of the catheter with the liquid swelling medium prior to use can be made very simple by application of a pressure to the walls of the compartment, whereby the liquid swelling medium will be transferred to the cavity, which may have a cross section narrowly surrounding the catheter, to activate the hydrophilic surface layer of the catheter.
The compartment for the liquid swelling medium may be entirely integrated with the cavity for the catheter, whereby the hydrophilic surface layer of the catheter will be activated immediately after completion of the production process, when the swelling medium has been introduced in the package. The gas-impermeable walls of the package will then protect the activated coating from drying out and provide a long time preservation of the low friction surface characteristic of the catheter until the moment of actual use.
It may be preferred, however, to separate the compartment for the swelling medium from the catheter cavity and provide the liquid flow communication as a relatively narrow passage to confine the swelling medium in the compartment until activation of the hydrophilic surface coating of the catheter is required immediately prior to use of the catheter.
To achieve this the liquid swelling medium may advantageously be confined in a storage body arranged in said compartment and made of a material which is able to serve as a storage for the liquid swelling medium and can discharge therefore the swelling medium by a simple physical action such as the application of an external pressure or squeezing effect. Such a material may typically be a spongy material or an absorbing gel.
The joint between the two sheets of film material of the package may advantageously be a welded joint which may be formed to allow easy opening of the package for withdrawal of the prepared catheter.
Such a welded joint may comprise a part provided between said compartment and said cavity as a peelable joint permitting separation of said compartment from said cavity after transfer of said liquid swelling medium from said compartment to said cavity for withdrawal of the catheter from the package.
Alternatively, such a welded joint may comprise a part at the end of the package remote from said compartment providing a peel-off joint to separate said sheets from each other for withdrawal of said catheter from the package.
In other embodiments of the type in which the compartment for the swelling medium is in liquid flow communication with the catheter cavity the package may comprise a first generally tubular part defining said cavity to narrowly surround the catheter and a second generally tubular part defining said compartment.
Embodiments of this type are quite simple and cheap in production. Typically, the first and second tubular parts may be integrally formed from an elongate hose-like member, one end section of which is expanded to constitute said second tubular part.
In a second series of embodiments, the compartment for the swelling medium is separated from the cavity for accommodation of the catheter, and the swelling medium is confined in said compartment in a liquid state until the intended use of the catheter.
In one embodiment of this type, the compartment for the swelling medium may be formed by a container arranged around a proximal part of said catheter not provided with said hydrophilic layer, said catheter passing through said container via sealed openings, said catheter and said container being arranged in said package to allow said catheter to be drawn through said container by withdrawal of the catheter from the package.
In order to reduce the amount of liquid swelling medium required for activation of the hydrophilic surface coating of the catheter, the latter may advantageously be provided with means preventing said swelling medium from getting into contact with internal or external surface parts of the catheter not provided with said hydrophilic layer for an activation period during which said medium is applied to the surface part provided with said hydrophilic layer.